4 free operating systems that aren't Linux

ReactOS 

While Linux and all of its variants have a completely new look, one of the biggest problems faced by new users is adapting to the new user interface after having used Windows for a long time. ReactOS is a free operating system that looks a lot like Windows. The unique thing about ReactOS is that it was built from scratch, to be like Windows. ReactOS can, in fact run many Windows applications and it’s free. The developers want users to be able to use ReactOS, along with the Windows software and compatible hardware without any issues. At just 48.9 MB, the latest version of ReactOS - 0.3.13 isn’t too large or heavy on resources - it’s a fraction of the size of a standard Windows operating system installation, but remember, is very limited in features. Those who don’t want to setup space on their hard drives and install ReactOS on it, there’s also LiveCD versions that can run off a CD or even disc images that will work on a virtual PC environment (such as Virtualbox).

Haiku Project 

BeOS was an operating system that was first developed back in 1991 and the last version 5.1 came out in late November 2001, after which the operating system ceased to exist. Haiku a community driven project, is influenced by the original BeOS operating system and has been under development, since the end of BeOS. The Haiku project aims to have the operating system to be compatible with BeOS binaries. BeOS, in its time was extremely responsive and had the right number of features and a very modern user interface. Haiku mimics most of the features and characteristics of that OS. Like ReactOS, Haiku is also available free for download as an ISO that you can burn on a disc and install on your PC. A virtual machine image file is also available. It’s a little bulkier than ReactOS, at close to 238 MB, but still much smaller than most mainstream Linux distributions and also, Windows.

OpenIndiana

OpenSolaris, the popular open source, Solaris-based operating system was developed and handled by Sun Microsystems. Soon after Oracle took over Sun, development of the platform seemed to slow down and developers decided to branch out the operating system into something called OpenIndiana. While OpenSolaris, like OpenIndiana has its roots similar to Unix and Linux, many of the applications and packages have changed, since then. There are more advanced file systems available, along with a bunch of other features, which have made the operating system robust. If you’re a Linux user and you’re looking for something similar, OpenIndiana may be the one to try. The OpenIndiana desktop DVD build for 32-bit operating systems weighs no more than 802 MB and 963 MB for a more portable, USB version. 

FreeBSD

The original BSD operating system was developed by the Berkeley University in California. Like OpenIndiana, it started back as Unix and since then, there have been several branches of the operating system. NetBSD (www.netbsd.org) and PCBSD (www.pcbsd.org) are two such branches, but the most popular one seems to be FreeBSD. For the biggest of Linux fans, it’s BSD that they look at once they’re done playing with. FreeBSD is more suited towards server and development environments, still enthusiasts continue to run a server at home running FreeBSD.

If you think we've missed out any major operating systems, please do post in our comments section below.